Penetrating UV-Protecting Compositions to Protect Wood and Lignin

Abstract

Disclosed herein are compositions for protecting a substrate against UV damage that comprise UV absorber(s), microemulsifier(s), polyol(s), and a water-based vehicle. In preferred embodiments, the compositions find application to protect lignin from degradation, or as primer coatings for wood surfaces, especially for use under UV-curable coatings. In other preferred embodiments the compositions are free of any film-forming polymer.

1 . A UV-protecting composition that comprises at least: (a) a UV absorber, (b) a microemulsifier, (c) a polyol, and (d) a water-based vehicle. 
     
     
         2 . The composition of  claim 1  wherein said UV absorber is selected from the group consisting of: a triazine UV absorber, a benzotriazole UV absorber, and blends thereof. 
     
     
         3 . The composition of  claim 2  wherein said triazine UV absorber is present from about 1% (w/w) to about 10% (w/w). 
     
     
         4 . The composition of  claim 2  wherein said triazine UV absorber is Tinuvin® 477. 
     
     
         5 . The composition of  claim 2  wherein said benzotriazole UV absorber is present from about 1% (w/w) to about 10% (w/w). 
     
     
         6 . The composition of  claim 2  wherein said benzotriazole UV absorber is selected from the group consisting of 3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxy-benzenepropanoic acid, C7-9-branched alkyl esters, C7-C9 linear alkyl esters, and blends thereof. 
     
     
         7 . The composition of  claim 2  wherein said UV absorber is Tinuvin® 5236. 
     
     
         8 . The composition of  claim 1  wherein said microemulsifier is present from about 1% (w/w) to about 30% (w/w). 
     
     
         9 . The composition of  claim 1  wherein said microemulsifier is selected from the group consisting of: Microflex® NX, maleated linseed oil, and blends thereof. 
     
     
         10 . The composition of  claim 1  wherein said polyol is present from about 1% (w/w) to about 60% (w/w). 
     
     
         11 . The composition of  claim 1  wherein said polyol is selected from the group consisting of: ethylene glycol, glycerol, methoxy-poly(ethylene glycol), poly(ethylene glycol), poly(ethylene glycol methacrylate), propylene glycol, sorbitol, and blends thereof. 
     
     
         12 . The composition of  claim 11  wherein said poly(ethylene glycol) has a molecular weight from about 100 amu to about 1000 amu. 
     
     
         13 . The composition of  claim 1  wherein said water-based vehicle comprises at least 10% water. 
     
     
         14 . A composition for protecting lignin from UV radiation that comprises at least: (a) a UV absorber, (b) a microemulsifier, (d) a polyol, and (d) a water-based vehicle. 
     
     
         15 . The composition of  claim 14  wherein said UV absorber is selected from the group consisting of: a triazine UV absorber, a benzotriazole UV absorber, and blends thereof. 
     
     
         16 . A primer coating having the composition of  claim 1  or  claim 14 . 
     
     
         17 . The primer coating of  claim 16  that additionally comprises an ingredient selected from the group consisting of: an acid, an anti-foamer, a bactericide, a base, a colorant, a defoamer, an emulsifier, a fungicide, a lubricant, a plasticizer, a solvent, a UV absorber, a wax, and blends thereof. 
     
     
         18 . The primer coating of  claim 16  that is applied at a use level from about 2 grams per square meter to about 20 grams per square meter. 
     
     
         19 . A method for protecting wood and/or lignin from UV degradation that comprises:
 (I) selecting a composition that comprises at least: (a) a UV absorber, (b) a microemulsifier, (c) a polyol, and (d) a water-based vehicle; and   (II) applying said composition on a substrate at a use level from about 2 grams per square meter to about 20 grams per square meter.